Evaluation Microstructure and the Mechanical Properties of Composite Material for Al-Matrix Reinforced by Ceramic Materials (Sic And Al2O3)

Abstract

In this investigation, the mechanical properties and microstructure of Metal Matrix Composites (MMCs) of Al.6061 alloy reinforced by ceramic materials SiC and Al₂O₃ with different additive percentages 2.5, 5, 7.5, and 10 wt.% for the particle size of 53 µ_m are studied. Metal matrix composites were prepared by stir casting using vortex technique and then treated thermally by solution heat treatment at 530 ⁰C for 1 hr. and followed by aging at 175 ⁰C with different periods. Mechanical tests were done for the samples before and after heat treatment, such as impact test, hardness test, and tensile test. Also, the microstructure of the metal matrix composites was examined by optical microscopy before and after heat treatment. The results of this work showed that precipitation of Mg₂Si as a secondary phase and improvements in mechanical properties with increase in the percentage of SiC and Al₂O₃.  Also, the results of SiC revealed an improvement in mechanical properties more than for Al₂O₃ such as hardness, impact strength, yield strength, tensile strength, increasing the plasticity constant (k) and decreasing the strain hardening exponent (n).